Vucinic is unsettled over the lack of action he's seen in recent games.
But Ranieri says: "He has to understand that the Coach wants him and the club does too, so he is 100 per cent staying guaranteed.
"There is happiness and a desire to have fun in the dressing room, this I can assure you. I have not spoken with Vucinic, but my door is always open.
"I don't believe that my being clear [with the players] is annoying. I have been in this world for 20 years. Evidently it's fine.
"You can't have the right key for everything obviously.
"If someone wants to make themselves understood then come and speak with me. I repeat. My door is always open."